Brush contact



- Sept. 14, 1937. E. KLEINMANN BRUSH CONTACT Filed Nov. 18. 1936 ril l l l/ INVENTOK I j/f/ g/A/MAWM ATTORNEYS.

UNITED STATES PATENT OFFICE BRUSH CONTACT Ernst Kleinmann, Berlin-Lichtenberg, Germany,

assignor of one-hah" 'to Alfred Mendel, Berlin- Lichtenberg, Germany Application November 18, 1936, Serial No. 111,559

In Germany 3 Claims.

Brush contacts in which two rows of brush Wires are fixed directly opposite to one another in a holder or box are needed for many purposes and in particular are required in the t-abulator industry, One of the requirements in such brush contacts is that the wires should be capable of relative displacement and therefore the wires in the one row must not be staggered relatively to those of the other. Instead the wires in the two rows must be directly opposite one another and they must exactly fill a clearly defined rectangular space in the holder.

At the present time the usual practice is to arrange the wires in the correct relative positions and to spray hot metal onto them to fix them and form a holder. The result of this is that the wires are annealed at their roots by the hot metal and thus lose their resilience or elasticity just at those points where their properties are most needed, namely, at the points where the wires leave the holder. Further the wires often get out of position during the spraying.

l I'he principal object of my invention is to secure the brush wires firmly in their holders Without causing them to lose their resilience in the way described above, and without allowing them to shift relatively to one another.

In manufacturing a brush contact according to my invention I take two holder parts each constituting one half of a holder in which there are one or more rectangular grooves and in each of these grooves I lay a row of brush wires. I unite these wires to the two holder parts and I then form` the two parts into a unit holder in such a way that the wires in the one row are exactly opposite to the wires in the other row.

My invention will be better understood by reference to the accompanying drawing in which,

Figure 1 is a perspective view of a brush contact made according to my invention,

Figure 2 is a section on an enlarged scale through the contact of Figure 1,

Figure 3 is a side View of a modified form of brush Contact,

Figure 4 is a section on the line IV-IV of Figure 3,

Figure 5 shows one stage in the manufacture of another modified form'of contact,

Figure 6 shows a later stage in the manufactureof this contact, and

Figure 7 is a perspective view of the finished contact.

Referring rst to Figures 1 and 2, I take two rectangular trough-shaped pieces of sheet metal I and 2 of suchV dimensions that each will just October 3, 1936 receive six brush wires 3 arranged side by side. After laying the row of brush wires in the groove that forms the trough in one of the rectangular sheet metal casing pieces I secure the wires to the casing by soldering, spot welding or spraying hot metal, but I take care to apply this treatment, not close to the points where the wires leave the casing, but further back, so that any loss of resilience occurs only at points well inside the casing. After making the second casing half in the same way, I next join the two casing halves together to form a unit as shown in Figure 1. This joining may be done in any convenient way as, for example, by soldering or welding or folding abutting flanges to the casing halves around one another.

It sometimes happens that the brush wires should be arranged in groups. In Figures 3 and 4 I have shown a contact with the wires arranged in two groups. It will be seen that there are two casing parts 4 and 5, each of which is divided into two trough parts by partitions 6 and 'l respectively. The length of each trough part is such that it will just accommodate three wires 3 side by side. These wires are secured in the trough parts in any convenient way, such as those described in connection with Figures 1 and 2.

In Figures 5, 6, and 7 I have illustrated a method in which the wires are secured in position by cold pressing and thus any risk of loss of resilience by the annealing action of hot metal is avoided. Two casing parts 8 and 9 are each so shaped that they present three grooves each just able to accommodate three wires side by side and each of depth a little greater than the diameter of the wires. Figure 5 shows the wires 3 assembled in the grooves l!) of the casing part 8. This part is then pressed so that metal at the ends of the grooves is bent inwards a little to overlap the end wires of each groove, as shown in Figure 6. The middle wire in each groove is not directly held in but is so iirmly held in position by friction, as a result of the cold pressing operation, that there is no tendency for it to shift when the brush contact is used. The two holder halves may advantageously be secured together by spot welding to form the holder shown in Figure '7.

It will be understood that in all the figures the dimensions are greatly exaggerated as the brush wires in practice are only from le to ,-26 mm. in diameter.

As the brush contacts illustrated are intended for use with the roller of a tabulator machine the free ends of the wires are ground away as shown in Figures 1, 3, and 7.

I claim as my invention:

1. In a brush Contact, two co-operating holder parts each formed with a rectangular groove and a plurality of brush wires sidevby side and rmly secured in each groove, said holder parts being secured together with the open mouths of the grooves in register and with the wires in the one groove directly opposite the wires in the other groove. l

2. In a brush Contact, two co-operating holder parts each formed with a plurality of rectangular grooves, a plurality of brush wires side by side and rmly secured in each groove of the one part, an equal number of brush wires side by side and rmly secured in each corresponding groove of the other part, said holder parts being secured together with the open mouth of each groove in the one part in register with the open mouth of the corresponding groove in the other part and with the wires in each groove directly opposite the wires in the said corresponding groove.

3. In the manufacture of a brush Contact, the steps which comprise lling a groove in a holder part with a plurality of brush wires arranged side by side, said groove being slightly deeper than the diameter of said wires, applying pressure to said holder part to force the edges of the groovesl 

